Learning Forum

[José Mantovani]

Hello guys!

I have here an experiment using hydrodynamic cavitation for pre-treatment of bagasse and sugar cane straw that will later be used to obtain bioethanol. The idea of the simulation is simply to visualize the fields of pressure, velocity and fraction of vapor for example of the phenomenon of cavitation only with water, without the mixture of sodium hydroxide plus the bagasse of the sugar cane. In the experiment there is no detailed information such as velocity, Reynolds stresses, there are no measurements, for example, through a Doppler laser speedometer or measurements wall pressure or skin friction. There is only one manometer at the inlet indicating the pressure supplied to the fluid by the pump. I would like to know if there is a way for the simulation to produce more cavitation than just that small region which is seen in the image below by the vapo fraction contour together with a real cavitation image occurring in the venturi tube. Any tips? Or perhaps an explanation as to how FLUENT can predict this phenomenon. Is it possible to approximate the results with the experiment? Regarding the issue of producing cavitation as in the photo, in every region divergent and not only near the walls of the tube as FLUENT does.

Or maybe I already have what I want however through this 2D longitudinal view I can not visualize how in the actual image where it is obviously 3D ... I did the 3D simulation with the exact dimensions of the geometry.

Hugs,

Mantovani.

 

[DrAmine]

Without any input or measurement could be hard. First of all go to 3D and then make some parameter optimization but without at least an integral bulk measurement (void holdup or pressure or mass flow rate of vapor at outlet) that would be numerical experimenting.  You need perhaps to tune the underlying coefficients of Zwart et. al model or the nucleation site of the Schner model.